Two step modification of textile materials

ABSTRACT

TEXTILES COMPOSED OF CELLULOSIC FIBERS OR BLENDS OF CELLULOSIC AND SYNTHETIC FIBERS ARE MODIFIED TO IMPROVE THE FLAT DRYING PROPERTIES THEREOF THROUGH TREATMENT WITH POLYFUNCTIONAL REACTANTS HAVING AT LEAST ONE ACID CATALYZABLE AND AT LEAST ONE ALKALINE CATALYZABLE GROUP. EITHER THE ACID CATALYZED OR THE ALKALINE CATALYZED REACTION MAY BE CONDUCTED FIRST. THE REACTIONS MAY BE CONDUCTED IN THE WET OR DRY STATE. THE ALKALINE CATALYST USED MAY BE ONE WHICH IS SUBSTANTIALLY NEUTRAL WHEN INITIALLY APPLIED TO THE TEXTILE BUT BECOMES STRONGLY ALKALINE AT ELEVATED TEMPERATURES. A REDUCING AGENT MAY BE ADDED TO THE TREATING BATH TO INHIBIT YELLOWING OF THE TEXTILE MATERIAL UNDER CURING CONDITIONS. AN AMINOPLAST RESIN MAY BE INCLUDED IN THE TREATING BATH. ACTIVE HYDROGEN CONTAINING COMPOUNDS MAY BE APPENDED TO THE TEXTILE THROUGH REACTION WITH REACTIVE GROUPS BOUND TO THE TEXTILE BY THE INITIAL REACTION BETWEEN THE POLYFUNCTIONAL COMPOUND AND THE TEXTILE.

F'IPSSO? United States Patent Int. Cl. D06m 15/54, 15/70 US. Cl. 8-1163 Claims ABSTRACT OF THE DISCLOSURE Textiles composed of cellulosic fibers or blends of cellulosic and synthetic fibers are modified to improve the flat drying properties thereof through treatment with polyfunctional reactants having at least one acid catalyzable and at least one alkaline catalyzable group. Either the acid catalyzed or the alkaline catalyzed reaction may be conducted first. The reactions may be conducted in the wet or dry state. The alkaline catalyst used may be one which is substantially neutral when initially applied to the textile but becomes strongly alkaline at elevated tem peratures. A reducing agent may be added to the treating bath to inhibit yellowing of the textile material under curing conditions. An aminoplast resin may be included in the treating bath. Active hydrogen containing compounds may be appended to the textile through reaction with reactive groups bound to the textile by the initial reaction between the polyfunctional compound and the textile.

This is a continuation of application Ser. No. 691,655, filed Dec. 18, 1967, and now abandoned, which in turn is a continuation-in-part of application Ser. No. 244,275, filed Dec. 13, 1962, and now abandoned.

This invention relates to methods for treating cellulosic materials to improve certain characteristics thereof, particularly the flat drying properties, to the cellulosic materials thus obtained and to certain cellulose ethers.

It is now well known that cellulosic materials can be treated with a textile resin to impart certain minimum care characteristics to fabrics produced from these textile materials. As a result of this textile resin treatment, fabrics having fairly satisfactory dry resiliency, i.e., good dry crease resistance or recovery, are presently being commercially produced in large quantities. It is characteristic of such fabrics, however, that they must normally be drip dried, i.e., hung dripping wet after being washed, if the fabric is to have a semblance of a pressed appearance when dried. The reason for this is that although substantial dry resiliency can be imparted to the fabric, a lesser degree of wet resiliency, i.e., wet crease resistance or recovery, is imparted to the fabric by the resin treatment. It is impractical to attempt to overcome this deficiency by applying more resin as severe embrittlement or weakening of the material results along with other undesirable features such as a harsh, raspy hand and poor comfort values if the material is to be used in a garment.

By the process of this invention, it is possible to produce fabrics having good wet as well as dry resiliency, thereby providing excellent flat drying fabrics, while at the same time retaining a higher percentage of the strength of the starting textile material than would be achieved with a conventional resin treatment, e.g., employing a known triazone. By this process, fabrics can be produced having at least as good residual strength and substantially better wet resiliency than is obtained by a conventional textile resin treatment. Frequently, fabrics having both increased residual strength and increased wet resiliency ice compounds utilized in accordance with this invention.

Furthermore, previously used polyfunctional compounds generally must be accompanied by additional compounds to build up the performance in either or both the wet and dry state. The polyfunctional compounds utilized in the processes of this invention may be utilized alone to provide excellent wet and dry resiliency properties in the fabric and, consequently, excellent flat drying properties. Also, the polyfunctional compounds utilized herein are highly eificient in their reactivity with hydroxy groups of cellulose, so that for a given performance requirement, less of the polyfunctional compounds utilized herein is required than would be required for other polyfunctional compounds.

It is an object of this invention to provide a novel proc ess for the modification of cellulosic materials whereby a high degree of wet and dry resiliency is imparted thereto.

It is another object of this invention to provide such a process wherein the dry and wet resiliency properties are provided by a single polyfunctional compound which is reacted under both acid and basic conditions, the response of the fabric to the treatment under basic conditions being superior to any cellulosic treating process known heretofore.

Still another object of this invention is to provide such a process wherein the residual strength of the cellulosic material is as high or higher than any previously known process for the modification of cellulosic materials.

These and other objects are accomplished in accordance with this invention by impregnating cellulosic material with (a) a reaction product of an acrylamide and an aldehyde, said reaction product containing at least three groups reactive with hydroxy groups of cellulose, at least two of said groups being reactive under conditions markedly different from the reactivity of at least one other of said groups and (b) a catalyst for the reaction of only one type of the groups with hydroxy groups of cellulose. The impregnated material is then exposed to conditions whereby the catalyzed groups react with hydroxy groups of cellulose and under which the groups of markedly different reactivity are substantially nonreactive with hydroxy groups of cellulose. The cellulosic material is therrexposed to conditions whereby the remaining type of reactive groups react with hydroxy groups. This reaction is preferably conducted in the presence of a catalyst for such a reaction.

The reaction product of an acrylamide and an aldehyde preferably contains at least two groups reactive with hydroxy groups of cellulose under textile resin curing conditions, i.e., acid-reactive groups, and at least one group reactive with hydroxy groups of cellulose under alkaline conditions, i.e., base-reactive groups. In this embodiment of the invention, permanent dry resiliency properties can be imparted to the cellulosic material by conducting the acid-reaction first and under textile resin-curing con ditions wherein the cellulosic material is substantially dry and in a flat state. In this manner, the reaction product is chemically afiixed tothe cellulose molecule through the cross-links formed, so that subsequent cross-linking operations can be conducted under any desired condition without destroying the dry resiliency properties of the cellulosic material. The base-reactive groups of the reaction product are then reacted with hydroxy groups of cellulose, preferably while the cellulosic material is swollen with a strong alkaline catalyst, whereby excellent wet resiliency properties are obtained.

Typical reaction products suitable for use in accordance with this invention include those derived from acrylamides, including alkylene-bis-acrylamides, and saturated or unsaturated aldehydes, preferably simple ones like formaldehyde.

Preferred reaction products are believed to have a formula characterized by wherein R is selected from hydrogen, lower alkyl and the residue of a saturated or unsaturated aldehyde; R is selected from hydrogen and lower alkyl, preferably methyl; and R is selected from hydrogen and lower alkyl; and X is selected from oxygen and sulfur.

The R O groups of the above compounds react with hydroxy groups of cellulose under textile resin curing conditions to give permanent dry resiliency properties. The -CR =CH groups of the above compounds react with hydroxy groups of cellulose, preferably in the swollen state provided by an alkaline catalyst, to give permanent wet resiliency properties.

The reaction under textile resin curing conditions is believed to provide cross-links of the formula:

(II) Cell-O-CHR X N-ii-C R =CHg Cell-O-CHR wherein Cell is the residue of a cellulose molecule of said material; R is selected from hydrogen, lower alkyl and the residue of a saturated or unsaturated aldehyde; X is selected from oxygen and sulfur; and R is selected from hydrogen and lower alkyl, preferably methyl.

The alkaline reaction is believed to provide a crosslinked structure of the formula:

Cell-O-CHR (III) Cell-O-OHR wherein Cell is the residue of a cellulose molecule of said material; R is selected from hydrogen, lower alkyl and the residue of a saturated or unsaturated aldehyde, and R is selected from hydrogen and lower alkyl.

In preparing the above compounds, aldehydes other than formaldehyde may be utilized, for example,- those derived from saturated or unsaturated aldehydes, whereby R in the Formulae above would be lower alkyl, e.g., acetaldehyde; vinyl, e.g., acrolein; acetyl, e.g., pyruvaldehyde; CH CH=CH-, e.g., crotonaldehyde;

wherein R R and X are as before, R being hydrogen, lower alkyl or CHR OR wherein R is as before. Typical compounds include that derived from acrylamide and glyoxal (wherein R R and R are hydrogen and X is oxygen) and the N-methylol, di-N-methylol derivatives thereof.

wherein R R R and X are as before, and x=16, e.g., N methylol methylene bis (acrylamide), methylene-bis-(N methylol acrylamide) and the like.

eg as derived from methylene-bis-acrylamide and glyoxal and the like.

Additional compounds suitable for use in accordance with this invention, though less preferred, are reaction products of haloacetamides and aldehydes, e.g., those characterized by the formula:

(v11) R*0CHR X N-ii-BPY RO-CHR wherein R is selected from CHR CHR CHR -cHcHR Y is halogen, such as chlorine, bromine and iodine; and wherein R R R and X are as given above.

Additional, but less preferred, compounds include:

(VIII) RL-CLHJN-CHRIOR4 R -&(IIJNCHR OIU wherein R R R and X are as given above, eg., as

where R R and R are hydrogen and X is oxygen.

In the above compounds, again in a less preferred embodiment, the

groups can have substituted therefor and sulfonium groups.

Of the above compounds, those derived from acrylamide per se and at least two moles of formaldehyde are highly preferred; i.e., N,N-dirnethylol acrylamide.

U.S. Pats. Nos. 2,837,511 and 2,837,512 disclose various processes for producing cellulose ethers, such as by reacting cellulose with polyfunctional compounds like N- methylolacrylamide in a two-step operation whereby the acid curing groups are first attached to cellulose (US. 2,837,512), after which the resulting cellulose ether is soaked in strong base solution at room temperature (US. 2,837,511) to produce a cross-linked product, which has only wet resilience properties. For example, a cellulosic fiber will acquire resiliency in the state in which the molecules thereof are cross-linked. For example, if a fiber is cross-linked while in a wet, swollen state, it will acquire wet resiliency only. Such a fiber will have a high spin rating, in that it will be resilient in the wet state, but will have a low tumble rating since no dry resiliency is imparted during wet cross-linking. The reverse is true. For example, a cellulosic fiber which is cross-linked in the dry state will acquire only dry resiliency and will be characterized by a high tumble rating and low spin rating. The only cross-linking disclosed in the above-identified patents occurs in the wet, swollen state, so that only wet resiliency is imparted to the rayon fibers. In other words, the monofunctional attachment of N-methylol acrylamide to cellulose which occurs during the initial acidside reaction disclosed in the above-identified patents is insufficient to impart satisfactory dry resiliency to the fibers treated therein, and consequently, no product disclosed in the above-identified patents would have satisfactory tumble ratings. The cellulose ethers disclosed in the above-identified patents, furthermore, are highly susceptible to chlorine damage as a result of attack of hydrochlorous acid on the free amido hydrogen atom of both the monofunctionally attached cellulose ether and in the final cross-linked product.

In the products formed by the polyfunctional compounds of this invention, permanent dry resiliency properties are built into the fabric during the initial dry state cure under acid conditions, i.e., under textile resin curing conditions. This enables the practitioner to conduct the cure under alkaline conditions at any desired moisture level in the fabric, while still obtaining a high degree of dry resiliency, e.g., as high as is obtained during the initial cure, along with the expected high degree of wet resiliency.

In addition, the degree of improvement obtained during the alkaline reaction with the polyfunctional compounds of this invention far exceeds that obtained with polyfunctional compounds similarly used in the art. For example, it is not at all uncommon during the alkaline reaction of the process of this invention to increase the spin rating of the acid-cured fabrics by as much as 2.5 units in conventional fiat dry ratings. On the other hand, the response to the alkaline reaction using previous polyfunctional compounds, rarely exceeds 1.0 rating unit and more often is about 0.5 rating unit. The desired reaction under alkaline conditions will occur at room temperature conditions after suitable ageing or the fabric can be heated to increase the rate of the desired reaction. The ageing procedure is a common practice involving wrapping the catalyst-impregnated fabric, preferably in a wet, swollen condition, in a roll in substantially wrinkle-free condition and permitting the rolled material to stand for a period of time sufficient to permit substantial reaction to occur between the base-reactive groups, e.g., -CR =CH and hydroxy groups of cellulose.

Alternatively, the rate of desired reaction can be increased 'by heating the wet, swollen cellulosic material to any desired temperature, preferably from room temperature up to about 200 C. where strong alkaline'catalysts are used and to temperatures of at least about 80 C. where milder alkaline catalysts, such as sodium bicarbonate and sodium carbonate, are utilized. The wet, swollen material can be heated on conventional equipment such as over hot cans, in tenter frames, 'with hot calendar rolls, conventional heating ovens, vat dryers, and the like. It is an advantage of the process of this invention that the alkaline-impregnated fabric reacts with hy droxy groups of cellulose at the CR =CH grouping at a sufficiently rapid rate at elevated temperatures, so that continuous processes are possible. For example, the fabric can be passed back and forth through a vat dryer, the dwell time being from about 1 to about minutes, to provide substantial reaction whereby the fabric is set in the fiat configuration in which it is passed through the vat dryer. The same effect can be noticed by passing over a plurality of cans heated to high temperatures, for example, up to about 130 C., or by passing on a tenter frame through a heated chamber. Preferably, the fabric impregnated with the alkaline catalyst is exposed to steam during the cure, in that steam greatly enhances the desired reaction.

The amount of polyfunctional compound which can be employed is not critical and the exact amount to be employed depends in part on the properties desired in the final product and the efficiency of the selected compound. For example, amounts in the range of from about 1 to about 40%, preferably about 5 to about 15% calculated on the weight of the dry textile material, or more or less, can be applied to the textile material as desired. As the pick-up of solution of the selected compound, if it is supplied as a solution, will range from about 50 to about on the weight of the textile material, a solution concentration should be selected which will provide the desired deposition of compound on the selected cellu= lose material under the conditions of pick-up. At very high pick-ups of the polyfunctional compound, no more improved results are obtained but fabric strength may be diminished. It is a distinct advantage of the present process, however, that far less strength loss is realized during the process of this invention than accompanies processes wherein a fabric is treated with both an acidreacting textile resin and a base-reacting reagent.

The polyfunctional compound may be applied to the cellulosic material as a single compound having at least two acid-reactive and at least one base-reactive group in the molecule as shown in Formula I, although a mixture of the compounds from which the polyfunctional compounds are prepared may be utilized. For example, a solution containing an acrylamide compound, at least 1.5 moles per mole thereof of formaldehyde and, if desired, an acid-acting catalyst may be prepared and padded onto the cellulosic material being treated. It is highly preferred that at least 2 moles of formaldehyde be utilized for each mole of acrylamide for the most efiicient process, although lower amounts of formaldehyde may be utilized, for example, down to about 1.5 moles of formaldehyde per mole of acrylamide. Under these latter conditions, however, the process is highly inefficient and less economical than where at least 2 moles of formaldehyde are present. In addition, the product produced from less than 2 moles of formaldehyde per mole of the acrylamide is characterized by increasing chlorine damage.

On the other hand, the acrylamide compound and excess formaldehyde, or other aldehyde compound, may be reacted in an aqueous solution of a mixture of these compounds, especially if heated, in which case the resulting product would have two acid-reactive groups and one base-reactive group in the molecule as set forth above, provided a sufficient amount of the aldehyde is utilized for reaction with substantially all amido-hydrogen atoms of the acrylamide.

The textile resin catalysts employed during the heating step under textile resin conditions are a well-known class of compounds and include the acid-acting compounds, that is, those compounds which are acidic in character under the curing conditions. The most common are the metal salts, for example, magnesium chloride, zinc nitrate and zinc fluoroborate and the amino salts, for example, monoethanolamine hydrochloride and 2-amino-2-methyl propanol nitrate. The amounts of catalyst to be employed are the same as those employed when using the usual textile resins, for example, up to about 20% by weight of the acid reacting compound employed, with the preferred range being from about 0.5 to about 10%.

While any acid-acting catalyst may be utilized, it is generally preferred to use a strong acid catalyst, such as zinc nitrate and the like, in that improved properties, such as improved wet'and dry resiliency properties are obtained with the stronger acid catalyst. When milder acid catalysts are utilized, it is recommended that higher temperatures and longer cure times be utilized. In this regard, compounds like zinc nitrate, which produce relatively low pH values in the fabric during curing, are considered strongly acidic, whereas compounds like magnesium chloride are considered mildly acidic.

Other additives commonly employed when using the usual textile resins can be employed in the process of this invention. For example, a small amount of a 'surface active agent can be added to insure uniform and satisfactory wetting out of the fabric, if an aqueous solution is employed. Softeners, for example the dispersible polyethylenes, can be added to improve the handle of textile materials being treated.

Conventional textile resins may be utilized in combination with the polyfunctional compounds disclosed herein to improve certain properties, such as the dry resiliency property, if desired. In general, however, no such improvement is necessary and, if anything, the addition of a textile resin tends to minimize the effect obtained by the use of the polyfunctional compound by itself. The term textile resin as used herein is in conformity with the generally accepted usage in the textile industry, i.e., it defines a thermosetting reagent which is applied to a textile fabric and reacted therewith when the dry fabric is heated, usually in the presence of an acidic catalyst, at a temperature usually between about 140 and about 200 C. These conditions are normally referred to herein as textile resin curing conditions. At this temperature, the reagent, even by itself, will ordinarily l'esinify in the presence of an appropriate catalyst, thus probably contributing to the use of the term resin treatment. However, it is to be understood that the term as used in the textile art is a misnomer in that in contradistinction to the generally accepted meaning of the term resin, textile resins are of relatively low molecular weights, are almost always water soluble and are often liquids. Included in the class of textile resins which may be added to the polyfunctional compounds of this invention are urea-formaldehydes and the melamine-formaldehydes, for example dimethylol urea and tetra and penta-methylolmelamines; the acrolein-urea-formaldehyde resins; the cyclic ethylene urea-formaldehyde resins, e.g., dimethylol cyclic ethylene urea and dimethylol dihydroxy cyclic ethylene urea, trimethylol-acetylene diurea and tetramethylolacetylene diurea; the triazones, e.g., dimethylol-N-ethyltriazone, dimethylol-N-hydroxy ethyl-triazone and the like.

The strong aqueous bases preferably employed as the catalyst in the second curing operation of the process of this invention are those having a pH of at least about as a 1% aqueous solution. The bases most commonly employed are the alkali-metal hydroxides, although other compounds such as sodium silicate, sodium carbonate and potassium carbonate which produce slightly lower pHs in the fabric during the wet curing stage can also be employed. If these latter type compounds are utilized, it is preferred that the temperature in the base curing step be increased preferably above about 80 C.

Although the alkali-metal hydroxides are preferred, additional base-acting catalysts may be utilized, e.g., potassium bicarbonate, potassium carbonate, alkali-metal phosphates such as sodium and potassium phosphate, barium carbonate, quaternary ammonium hydroxides and carbonates, e.g., lauryl trimethyl ammonium hydroxide and carbonate and the like.

These bases are usually employed as about 0.2% to about 16% solutions, preferably about 2 to about 16%. The exact concentration, while not critical, will affect the results obtained. The concentration which gives the optimum result will depend in part on the percent pick-up of the base by the textile material, the temperature at which the reaction is conducted and the amount of base consumed in the reaction. If a highly acidic group is released during the reaction, the amount of base applied to the textile material should be at least the amount that will be consumed by that group. Generally, a 3% to 10% aqueous solution of base is preferred when the pick-up is between about 30% to 130% calculated on the weight of the dry cellulosic material.

In carrying out the initial heating step of the process of this invention, the cellulosic material uniformly impregnated with the polyfunctional organic compound is heated under textile resin curing conditions in the pres ence of a textile resin catalyst, for example an acid-acting catalyst. As stated before, the polyfunctional compound containing at least two acid reactive and at least one base reactive group can be that which is initially applied to the textile material or can be the product of an in situ reaction of the acid-reactive group contributing compound and the base-reactive group contributing compound. Under ordinary conditions this steps employs conditions identical to that of a conventional resin treatment. For example, the selected reagents can be applied to the cellulosic material by padding, spraying or applicator roll and then passed through squeeze rolls, if neces sary, to achieve the desired pick-up of the reagents.

As these reagents are ordinarily applied as aqueous solutions, the cellulosic material is dried and then heated to the appropriate temperature, for example about to about 200 C., preferably about to about C. to produce the desired intermediate cross-linked cellulosic ether product. When employing fabric, these steps of drying and curing are conducted while the fabric is free from extraneous wrinkles, usually in a smooth open width condition. Conventional curing equipment is suitable for this operation. For example, when employing a fabric, the reagents can be applied with the usual equipment and then passed through squeeze rolls and dried, e.g., at room temperature or while the fabric passes through a hot air oven or over heated cans. In production, it is preferred to conduct the heating operations in a tenter frame to maintain the desired dimensions.

The thus treated cellulosic material is then ordinarily given a thorough wash to remove the catalyst and any unreacted reagents. If suflicient reagents are employed in this step, the cellulosic material will be found to possess a high degree of dry resiliency and somewhat improved wet resiliency at this stage. The textile material is then contacted with the desired base-acting catalyst.

When these compounds are utilized, the reaction can be reversed. For example, the base reaction can be conducted initially followed by the acid reaction. In this manner the initial cellulose ether would be characterized by high Wet resiliency properties which would be permanent under the conditions by which the acid reactive groups are reacted with hydroxy groups of cellulose provided at least two base-reactive groups are present in the polyfunctional compound. Generally, it is more preferred, however, to conduct the acid reaction initially followed by the base reaction.

The step of contacting the cellulosic material with the desired base acting catalyst employs conditions generally employed in the textile trade and the necessary techniques will be apparent to those skilled in the art. For example, impregnating the cellulosic material with the selected base acting catalyst can be accomplished in a manner similar to those employed in the previous step. The cellulosic material can be moistened by dipping in an aqueous solution of the selected base and squeezed through rollers to achieve the desired pick-up of the base. The impregnated material is then maintained at the selected temperature for a time sufiicient to insure substantial reaction between the base-reactive groups, e.g., -CR =CH and hydroxy groups of cellulose. It is ordinarily not preferred to maintain the cellulosic material in the presence of a large excess of the aqueous base solution because of the tendency of large excesses of base and water to sometimes interfere with the desired reaction. For this reason, the textile material is ordinarily maintained with a pick-up of from about 30% to about 130% calculated on the weight of the dry textile materia[l).7'I'he preferred pick-up is from about 50% to about 10 o.

The temperature at which substantial reaction between the base-reactive groups, e.g., CR =CH and hydroxy groups of cellulose occurs in the presence of the strong aqueous base can be varied over a fairly wide range, e.g., from about 20 to about 100 C. or higher if preferred, preferably between about 50 and about 100 C. although higher temperatures may be utilized if desired. Temperatures in excess of about 80 C. are preferred when mild alkaline catalysts are utilized. Room temperature is preferred for its convenience when the batch process, i.e., the process wherein a roll of impregnated fabric is aged until substantial reaction occurs. As noted above, it is also preferred that the alkaline cure be conducted in the presence of steam in that the desired degree of reaction is accomplished in much less time by this expedient. The thus treated cellulosic material is ordinarily then given a thorough wash to insure removal of any excess base and any byproducts of the reaction.

Textile materials which can be treated according to the processes of this invention are those in which the anhydroglucose units are chemically substantially unmodified. Thus, the term cellulosic textile material when used herein means any textile material comprising fibers within the above definition, e.g., cotton, paper, linen, jute, flax, regenerated cellulose fibers, including viscose rayon, in the form of staple, yarn and fabrics. This invention is directed primarily and preferably to cellulosic textile fabrics, either knitted or woven, preferably woven. However, the advantages of this invention can be achieved by treating the cellulosic fibers, yarns, or threads employed to produce these fabrics. The thus treated material, when woven or knitted into fabric will produce a fabric having better wet and dry resiliency than identical fabric woven from identical untreated yarn or thread. Moreover, the properties of the staple yarn and thread are modified in a desirable fashion. For example, the staple is less prone to compression into hard masses during wet or dry processing.

Satisfactory results can be achieved employing cellulosic materials containing both cellulosic and non-cellulosic fibers, especially if the non-cellulosic fibers have minimum care characteristics of their own. For example, the wet and dry resiliency of fabrics formed from a mixture of polyester, such as poly(ethylene terephthalate) polyamide such as poly(hexamethylene adipamide) or acrylic fibers, such as polyacrylonitrile and copolymers containing at least about 85% combined acrylonitrile filaments or fibers with cotton or rayon can be improved by this process. Obviously, if the non-cellulosic fibers have low minimum care characteristics, the improved characteristics of the materials treated according to the processes of this invention will be more readily apparent when the cellulosic content of the fabric is substantial, e.g., about 40% or more by weight. As stated above, the invention is primarily directed to fabrics, preferably consisting essentially of cellulosic materials, especially cotton. Bleached and usually also commercially mercerized or printed fabric, e.g., printcloth, broadcloth, and oxford cloth, is usually employed as the starting fabric.

After the initial curing step, the cellulosic material preferably contains at least about 1.8 unsubstituted hydroxy groups and at least 0.05 hydroxy groups per anhydroglucose unit substituted through two ether linkages by a radical having a terminal grouping reactive towards hydroxy groups of cellulose; In the usual instance, as where the acid-reactive group of the polyfunctional compound is reacted first, the substituent is base-reactive.

Such degree of substitution is preferred for the desired cross-linking reaction to take place to a satisfactory extent. Preferably, there are at least two unsubstituted and, more preferably, at least 2.5 unsubstituted hydroxy groups per anhydroglucose unit for the same reason. Of the remaining hydroxy groups, an average of at least 0.05, more preferably 0.20.5 hydroxy groups per anhydroglucose unit is substituted through an ether linkage to one of the R groups set forth above.

In addition to the preferred number of free hydroxy groups and reactive radical-substituted groups, the cellulosic material can have a minor proportion of hydroxy groups substituted with ether or ester groups, e.g., lowerhydrocarbon esters including the acetate, propionate,

10 butyrate, benzoate, sulfate, phosphate, aryl and alkyl esters; and lower alkyl ethers including methyl and ethyl; and hydroxyalkyl, such as hydroxyethyl and carboxymethyl ethers.

In some instances, the addition of reducing agents, such as alkali-metal borohydride, such as sodium and potassium borohydride; alkanolamine sulfites, such as monoethanolamine sulfite, monoisopropanolamine sulfite and others containing up to about 8 carbon atoms in the alkyl chain and the like can be applied to the cellulosic material being treated to inhibit any yellowing which may tend to occur under setting conditions in the garment state. Furthermore, when sodium borohydride is applied along with sodium bicarbonate or sodium carbonate, the time of curing is reduced, e.g., to 30-60 seconds with no yellowing of the fabric when steam is used, whereas without steam as much as 5 minutes would be required to get the same result.

The cellulose ethers formed during the acid-side cure above may be reacted with active hydrogen compounds in addition to cellulose. Also, in most instances, a sufiicient number of terminal ethylenically unsaturated groups remain after the alkaline reaction to enable further reaction to take place between the cellulose ethers and other active hydrogen compounds to form cellulose ethers of the formula:

Cell-O-CHR' wherein Cell is the residue of a cellulose molecule of the cellulosic material, R' is selected from hydrogen, lower alkyl and the residue of a saturated or unsaturated aldehyde, R is selected from hydrogen and lower alkyl, preferably methyl, X is selected from oxygen and sulfur and Z is the residue of an active hydrogen compound wherein the active hydrogen atom is linked to an atom selected from the group consisting of sulfur, nitrogen, phosphorus and oxygen.

In this manner additional properties can be imparted to the cellulose ethers produced in accordance with this invention, as with active hydrogen compounds like hydrogen sulfide, mercaptans, ammonia, amines, phosphites and alcohols. Representative compounds include hydrogen sulfide, benzyl mercaptan, octadecyl mercaptan and the like; ammonia, piperidine, octyl amine, morpholine, ethylene diamine, octadecylamines, p-toluidine and the like; diethyl phosphite, dibutyl phosphite, diphenyl phosphite and the like; aliphatic alcohols, cellulose esters and ethers as set forth above, and the like.

Preferred embodiments of the present invention are shown in the following examples. The physical properties of the fabrics treated according to the process of this invention were determined according to accepted standard methods. Tear strength was determined by A.S.T.M. Test designation D-l424-59. Tensile strength was determined by A.S.T.M. Test designation D-39-59 (No. 10). Crease recovery angle was determined by A.S.T.M. Test designation D-1295-53 T. See A.S.T.M. Standards for Committee D-13 on Textiles," (1959). Flat dry ratings were by A.A.T.C.C. Test designation T-88-1958.

EXAMPLE I Preparation of N,N-dimethylolchloroacetamide To 1620 gms. of 37% formaldehyde (20 moles), adjusted to a pH of 7.5 with 1 N-sodium hydroxide solution and heated to 40 C. are slowly added 935 gms. of 2- chloroacetamide (10 moles), with the concomitant addition of 1 N-sodium hydroxide solution to maintain the pH as close to 7.5 as possible. Complete solution of the 2-chloroacetamide is achieved after about 1.5 hours, after which the pH is adjusted to exactly 7.5 and the solution is allowed to cool to room temperature and stand overnight. Water is then added to a total weight of 4600 gms., thereby giving a solution containing 33% by weight of the reaction product so produced.

EXAMPLE II The aqueous reaction product prepared according to the procedure of Example I is made up to aqueous solu- 12 hydroxide solution. To this solution is added 710 gms. of acrylamide (10 moles) and 3 gms. of methylhydroquinone inhibitor. With the pH still held at 10.0, the solution is heated at 60 C. for one hour, cooled and tions of the following compositions: 30% of the solu- 5 than neutralized to 3 PH of 75 by the addition 3 non of Example 1% or 15% of mm nitrate hexahy' N-hydrochloric acid. Sufficient water is then added to draw 6% of Moropol 700 Polyfithylene Softener and increase the total weight to 2660 gms. thereby givin /3% of Surfomc N-95 surfactant. The resultant solua solution containing 50% b Wei ht of the reactio; tions are applied to 136 x 64, 4.3 oz./yd. (in the greige) roduct so reduced y g bleached and mercerized cotton broadcloth by padding 10 P p and then squeezing through nip rolls at 60 lbs. per square EXAMPLE V inch pressure to provide a pick-up of about 75% based The t procedure of Example IV is followed except that fi g g the g g fi i i instead of employing a molar ratio of formaldehyde to o f an en cure w smoo y Passing t mug acrylamide of 2:1, a ratio of 2.5 :1 is used. Essentially a curing oven at about 177 C. for 1.5 minutes. Samples similar results are obtained of the resultant fabrics are tested for physical properties. Further samples are padded to a pick-up of about 75% EXAMPLE VI by the techlilciue wlth 2% or 4% mine The procedure of Example IV is followed except that Ous Sodmm hydroxlde contfunmg 05% of a instead of employing a molar ratio of formaldehyde to (Mercerol These fab,ncs are rolled wrapped m acrylamide of 2:1, a ratio of 3:1, is used. Essentially polyethylene film and maintalned at room temperature similar results are obtained for about 16 hours, and then thoroughly washed in water and detergent, and dried. The resulting fabrics are then EXAMPLE VI tested for physical properties. The results of these tests The aqueous reaction products prepared according to are shown Table I belowthe procedures of Examples IV, V and VI are made up TABLE 1 Sodium Dry fill Dry fill hydroxide tensile tear Spin Tumble treatment, strength strength fiat dry flat dry Sample percent (lb. (gm rating rating Control 66. 8 700 1. 1. 0 None 38. 9 784 2. 2 3. 4 1. Cured with 1% Zn(N03)z6H;O-{ 2 34.6 604 3.2 3.3 No.2 33".? 55% 3'5 2'2 2. Cured with 1.67

Memos 2 32;; :2: 3;: 2;:

EXAMPLE III to aqueous solutions of the following composition: 10% The procedure of Example H is followed, employing (solid s) of one of the above-mentioned reaction products, a resin mixture containing the aqueous reaction product 40 1% Zlnc filtrate hexahydfate catalyst, 6% MOFOPO1 700 of Example I (13.5, 24 or 27%); a modified melamine polyethylene softener and 13% Surfonic N-95 surfactant. textile r i 0f Aefotex P 21 tfiaZOIle The resultant solutions are applied to 80 x 80, 3.7 oz./ f' f 1 t( 1; f( g gl q)o 213 8 N47); a yd. (in the greige) bleached and mercerized cotton print zinc mtrate cata ys 0 o n 3 2 2 or a magcloth b addin and then th nesium chloride catalyst (2% of catalyst MX); 6% of a at g h Squeezmg ig 1 1/ 7 of a per square lIlC pressure to provi e a pic -up Polyethylene softel-ler (Morop O1 700) and 3 0 of about 757 based on the wei ht of th (1 fabric surfactant (Surfomc N-). The physical properties of g e TY the thus treated f b i both b f and ft ageing with The fabrics are dr1ed over hot cans and then cured while sodium hydroxide solution are recorded in Table II. smooth by passing through a curing oven at about 177 TABLE II Dry fill Dry fill Spin Added resin tensile tear fiat Tumble Reaction product of (percent Sodium hydroxide strength strength dry flat dry Example I (percent) solids) Catalyst after treatment (lb (gm.) rating rating 0 7% N-17 1% 1(N0a)26 z go 7% 1%ZMNO916H20 zi i i'iliir'r's 42:6 e72 310 4:6 N 37.1 ass 3.1 4.3 27 5% N47 2% MX 2 213. 16 hours 645% N47 2% MX {:g s yl idi'is 23: g% lg Z 15% M4 2% MX htfiifiria'raaszz: 41:6 ass 3:6 4:3

EXAMPLE IV 1620 grns. of 37% formaldehyde (20 moles) is adjusted to a pH of 10.0 by the addition of 5 N-sodium C. for 1.5 minutes. After washing, the fabrics possess the physical properties shown in Table III.

13 EXAMPLE VIII TABLE VII Sodium hydroxide treatment Dry fill Dry fill Concentensile tear Spin Tumble tratlon Treatment strength strength fiat dry flat dry (percent) time (hr.) (lb.) (gm) rating rating Control 65. 6 1168 1. 1. 0 0 0 40. 708 l. 4 3. 4 2 35. 9 580 2. 9 4. l 2 3. 5 30. 8 508 4. l. 4. 4 5 32. 5 484 3. 9 4. 0 0. 5 37. 3 540 2. 7 3. 0 3 5 2 34. 4 496 3. 7 4. 4 4 31. 5 444 4. 4 4. 7 0. 36. 5 588 2. 0 3. 8 6 1 29. 3 548 4. 1 4. 4 2 33. 3 504 4. 3 4. 6

EXAMPLE IX The procedure of Example VIII is repeated except that the zinc nitrate catalyst concentration is varied while the concentration of the reaction product of Example IV is held constant at 10% (solids). The properties of the fabrics thereby obtained are shown in Table V.

EXAMPLE XII The aqueous reaction product prepared according to the procedure of Example IV is made up to an aqueous solution of the following composition: 6% (solids) of the above-mentioned reaction product, 0.6% zinc nitrate hexahydrate catalyst, 6% Moropol 700 polyethylene soft- TABLE V Dry fill Dry fill Sodium tensile tear Spin Tumble 8 a ys 00112811 1'8 011 y 0X 8 S reng S reng a ry 8 ry Ctlt tti hdrid t th t thfltd fltd (percent Zn(NO1) 261110) treatment (1b.) (gm rating rating Control 71. 6 1, 148 l. 0 1.0 None...... 42.5 688 1.2 4.0 2% 32. 6 436 4. 4 4. 5 1. 25 {None 39. 7 576 1. 8 4. 1 2% 31. 5 416 4. 2 v4. 6 1, {None 36. 8 568 2. 4 4. 1 2% 29. 5 392 4. 6 4. 8

EXAMPLE X ener and /s% Surfomc N-95 surfactant. The resultant The procedure of Example VIII is repeated, employing a solution containing the aqueous reaction product of Example IV (10% solids), 1% of zinc nitrate hexahydrate catalyst, a polyethylene softener (6% Moropol 700 or 10% Syn-Soft LS) and /3 of Surfonic N-95 Surfactant. After the sodium hydroxide treatment, the fabrics possessed the physical properties shown in Table VI.

TABLE VI Dry fill Dry fill tensile tear Spin Tumble strength strength flat dry flat dry Polyethylene softener (1b.) (gm.) rating rating 6% MOrOpOl 700 37. 1 578 4. 1 4. 1 10% Syn-Soft LS 41.1 638 4.2 4. 0

EXAMPLE XI solution is applied to fabric of the type employed in Example VII, and the procedure described therein is exactly followed.

Thep'hysical properties of a sample (designated A in Table VIII) of the fabric thereby obtained are measured. Other fabric samples are padded with 2% aqueous sodium hydroxide, placed in a steam atmosphere in a conditioning oven at 100 C. for 5 minutes and then immediately washed and dried. The physical properties of a sample (designated B in Table VIII) of this fabric are also measured.

TABLE VIII Dry fill Dry fill tensile tear Spin Tumble strength strength fiat dry flat dry Sample (lb (gm.) rating rating EXAMPLE XIII The procedure of Example VIII is repeated, using the solution of Example XI, but in this case the after-treat- 15 ment with 2% aqueous sodium hydroxide is conducted in a steam autoclave (120 C. at 20 lbs. pressure) for 5 minutes, and the fabric is then immediately washed and dried. Table IX shows the physical properties of the thus treated fabrics.

A repetition of the procedure of Example XIII, but using hot cans to induce the 2% sodium hydroxide resodium hydroxide reaction leads to essentially similar results.

TABLE X Sodium hydroxide treatment 2% for 16 hours After 10 launderings in Kenmore automatic Physical property measured None Initial Washer 260 227 Wet 189 268 249 Spin flat dry rating 2. 6 4. 1 4.1 Tumble flat dry rating 4. 3 4. 7 4. 7 Abrasion resistance:

(a) Flex (fill) 378 386 (b) Accelerator (percent wt.

loss 7.1 6. 5 Chlorine damage (percent loss). 2.5 3. 4

Nitrogen analyses (Kjeldahl method) on the fabrics at different stages in the process hereby show that the reaction of the N,N-dimethylolacrylamide with the cotton EXAMPLE XV cellulose is virtually quantitative (see Table XI). A repetition of the procedure of Example XIII, but TABLE XI using steaming in the Hoffman press to induce the 2% N11t rogle1nana1ylsisoi sodium reaction leads to essentially similar results. a mp9s Percent 01 EXAMPLE XVI 3 30 applied to The aqueous reaction product prepared according to sample Percent! fabric the procedure of Example IV is made up to an aqueous 1, pad and dry only 0.696 100 2. P d,d d h 0. 698 100 solution of the following c omposmon. 10% solids of a 33 hydroxide the above-mentioned reaction product, 1% 21110 n1trate 3 nd wash 0.676 97 hexahydrate catalyst, 6% Moropol 700 polyethylene soft- 5 ener, and /3% Surfonic N-95 surfactant. The resultant EXAMPLE XVII solution is applied to fabric of the type employed in Ex- The procedure of Example XVI is repeated, but in this ample I Ito a pick-up of 75%, as described therein. The case the reaction in the presence of 2% aqueous sodium wet fabric is dried by passage through a commercial hydroxide is accomplished by passing the wet fabric tenter frame at 120 C. and then cured by a second pasthrough a commercial tenter frame at 150 C. for 1 minsage through the tenter frame at 163 C. for 1 minute. The ute. The properties of the thus treated fabric are shown physical properties of samples of this fabric are measured. in Table XII.

TABLE XII D fill D m1 creas1e recovery 8 1 T bl 11 um 8 t sile tear a nhliiii i iat flat Sodium hydroxide strength strength dry dry treatment (1b.) (gm.) Dry Wet rating rating None a9. 9 730 201 19s 3. 0 3. 9 2% at 150 0. IO! 1 111111.... 35. 0 584 257 243 a. s 4. 5 Control s2. 5 776 150 140 1. o 1. 0

EXAMPLE XVIII The remainder of the fabric is padded to a pick-up of about with 2% aqueous sodium hydroxide containing 1% of a surfactant (Mercerol GV), rolled up, held at room temperature for 16 hours, washed in 0.5% acetic acid, thoroughly washed in water and detergent, and dried. The physical properties of the resultant fabric are shown in Table X, together with the same properties after typical home laundering procedures.

The procedure of Example XVI is repeated, but in this case the reaction with 2% aqueous sodium hydroxide is accomplished by passing the wet fabric through an atmosphere of steam for nine minutes at C. in a Vat Ager. The process is also repeated using 4% aqueous sodium hydroxide or 2.5% aqueous sodium carbonate in place of the 2% aqueous sodium hydroxide. The addition of 0.2% sodium borohydride to the alkali solution prevents any yellowing of the fabric during the steaming process. The properties of the thus treated fabrics are shown in Table XIII.

17 EXAMPLE XIX The procedure of Example IV is followed except that moles of methacrylamide is employed in place of 10 moles of acrylamide. The aqueous reaction product thereby obtained is employed in the procedure of Example VIII and essentially similar results are obtained.

EXAMPLE XX 154 gm. of methylenebisacrylamide (1 mole) is gradually added to 162 gm. of 37% formaldehyde (2 moles) which has first been adjusted to a pH of 8.5 with 1 N-sodium hydroxide solution and heated to a temperature of 60 C. The temperature is maintained at 60 C. for one hour, water added to a total weight of 714 gm. and the solution cooled. The final solution contains 30% by weight of the reaction product so produced.

EXAMPLE XXI The procedure of Example VIII is repeated, except that the aqueous reaction product of Example XX is employed in place of the reaction product of Example IV. Essentially similar results but with lower Flat Dry Ratings, are obtained.

EXAMPLE XXII The reaction product of glyoxal with two molar equivalents of acrylamide is used in place of the reaction product of Example IV in the procedure of Example VIII. This reaction product is prepared in the following manner: Two hundred and eighty-five gms. of 40% glyoxal (2 moles) and 95 gms. water are adjusted to a pH of 8.0 with 1. O N-sodium hydroxide solution. Two hundred and eighty-four gms. of acrylamide (4 moles) and 3 gms. of methylhydroquinone inhibitor are added and the mixture is heated at 50 C. for 1.5 hours and cooled. Results essentially similar to those of Example XXI are obtained when this reaction product is employed in the procedure of Example VIII.

EXAMPLE XXIH The procedure of Example VIII is repeated except that the reaction product of 1 mole of acrolein and 3 moles of acrylamide condensed at pH 2 by heating at 60 C. for 30 minutes is employed. The fabric is padded with a 50% solution (adjusted to pH 9) of the reaction product containing 3 moles of formaldehyde. Results essentially similar to those of Example XXI are obtained.

That which is claimed is:

1. A process for improving the properties of a fabric which comprises:

(a) impregnating a cellulosic textile fabric with the reaction product of more than 1 and up to about 1.3 moles of an aldehyde and 1 mole of acrylamide or chloroacetamide, and either an acid catalyst or an alkaline catalyst Which is substantially neutral on the fabric but becomes strongly alkaline at temperatures in excess of C.;

(b) reacting said reaction product and hydroxy groups of cellulose to form an ether linkage therebetween;

(c) thereafter impregnating said fabric with an acid catalyst if a basic catalyst was used in step (a) or a basic catalyst if an acid catalyst was used in step (a);

(d) drying said fabric at a temperature insufiicient to initiate substantial reaction; and

(e) subjecting said fabric to curing conditions.

2. The process as defined in claim 1 wherein the fabric is reacted initially in the presence of an acid-acting catalyst with said cellulosic fabric being in a dry, unwrinkled state and subsequently is reacted in the presence of an alkaline catalyst and sufiicient moisture to provide swell= ing of the cellulosic fabric.

3. The process as defined in claim 1 wherein the fabric is reacted initially in the presence of an alkaline-acting catalyst with said cellulosic fabric being in a wet swollen state and subsequently is reacted in the presence of an acid-acting catalyst with said cellulosic fabric being in a substantially dry unwrinkled state.

4. The process as defined in claim 3 wherein the alka line catalyst is an alkali metal bicarbonate.

5. A cellulosic textile fabric produced according to the process of claim 1.

References Cited UNITED STATES PATENTS 3,102,773 9/ 1963 Needleman 8116.3 2,837,511 6/1958 Mantelle 8116.3 3,301,631 1/1967 Mauldin 8116.2 3,418,067 12/1968 Mauldin et a1 8116.2 3,558,263 1/1971 Baitinger 8-116.3

GEORGE F. LESMES, Primary Examiner J. C. CANNON, Assistant Examiner US. Cl. X.R.

8-l10, 111, 115.6, 115.7, 116 P, 116.2, 120, 125, 129, DIG. 14, DIG. 21; 28-75; 38144; 117139.4; 2-243 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Michael V. Lock Inventofls) I It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The term of this patent subsequent to November 2,} 1988, has been disclaimed.

Signed and sealed this 20th day of May 1975.

(SEAL) Attest: C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks USCOMM-DC 60376-P69 U,S GOVERNMENT PRINTING OFFICE: e 69. 93 O F ORM PO-1 050 (10-59) 

